1. Field of the Invention
This invention relates to the protection of electrical interconnections. Such interconnections may be between two or more electrical cables (i.e. in-line or branch joints), between two or more pieces of other electrical equipment such as transformers and switchgear, but which may also include another cable or between cable and equipment, including cable adapters and terminations. Such an interconnection usually needs to be protected against ingress of moisture to interconnected conductors, and to provide electrical insulation therearound. Additionally, at voltages above about 10 kV, some form of electrical stress control is usually also desired. The invention is generally applicable to electrical interconnections at low voltage, typically around 1 to 10 kV, at medium voltage, typically around 10 to 36 kV, and also at high voltage, typically greater than 36 kV.
2. Description of Related Art
Various technologies exist for protecting such interconnections, some of which are more applicable to one voltage range rather than another, and some applicable to cables, for example, of one material, for example polymeric, then another, for example paper. Amongst these technologies may be mentioned polymeric heat shrink, elastomeric push -on and roll-on, elastomeric hold-out, tape winding, hot bitumen filling, and cold-pour resin systems. Pending Raychem U.S. patent application Ser. No. 08/138,360, the contents of which are now published in International Application Publication No. WO 95/11543, discloses a power cable joint which is filled by a compressible sealant material such as gel, which has been found to have surprisingly good performance.